JetBlue off runway on Christmas in Boston

[BDL SLF]

I'm not allowed to post a URL until I have 10 posts (I have 6) but wanted to let people who may have missed it know a JetBlue A320 ended up facing the wrong way off the runway at KBOS on Christmas.

[DaveReidUK]

https://cbsnews1.cbsistatic.com/hub/i/r/2017/12/26/74684f7a-69da-4fd9-8299-95c58596e3c7/resize/620x/48aafd0a2777d3bd56381d530d4a8146/boston-taxiway-plane-2017-12-25.jpg

[Bigpants]

Interesting!. Hopefully no causalities.

[B2N2]

It was a taxiway.
Hit a patch of clear ice.
That’s it.
No more no less.

[The Ancient Geek]

Casualties are unlikely at such low speeds.

Human factors are important here, our ability to read the conditions and slow down accordingly is doubtful at best and when it does start to move in the wrong direction we instinctively hit the brakes, making matters worse.
It helps to know exactly where your wheels are and keep them in the worn track (if any) but ultimately the airfield is responsible for keeping the surface safe.

There but for the grace......

[piperpa46]

Causality should probaly have read causal factors

[b1lanc]

Snow ended about noon or an hour later but I was getting weather warnings from work well into the until the evening for flash freeze, winds and blowing snow. Crew allegedly told tower they only needed a tow after sliding off taxiway but tower dispatched emergency vehicles. Where's Patroni when you need him.....

[number0009]

It was a taxiway.
Hit a patch of clear ice.
That’s it.
No more no less.
Initial report I saw indicated it hit ice turning on to the taxiway. Following day, 12-26 there were several news stories contrary to that.


....AirBus A320 slid off of the runway, it span out of control, performing a 180 degree turn. It eventually faced toward the opposite direction...

[DaveReidUK]

The non-aviation press typically use "runway", for effect, when they mean any paved area on the airport.

If they actually make a point of saying "taxiway", then that's what they mean.

[b1lanc]

If you listened to the pax interviews, one said the were spinning in circles, another said they were tail wagging after landing while still on the runway, a third said she was concerned as soon as they turned off the runway(?), a fourth said they wound up in a snow bank (3 inches of snow).

Crew called for emergency trucks saying they were taking out signs and later were in the grass by Papa and Echo requesting a tow.

[number0009]

If they actually make a point of saying "taxiway", then that's what they mean. Who is they?

View the video and you can clearly see the skid tracks on the unpaved surface left by the A320. Result of a cautious slow speed taxi incident? VIDEO: JetBlue plane from Savannah slides off taxiway at Boston?s Logan Airport | SavannahNow (http://savannahnow.com/news/2017-12-26/video-jetblue-plane-savannah-slides-taxiway-boston-s-logan-airport)

http://i.dailymail.co.uk/i/pix/2017/12/26/05/479296DF00000578-5212313-image-a-120_1514266082925.jpg

[number0009]

If the A320 departed a nice straight section of taxiway as some news reported the crew may have learned how not to taxi in those conditions.

[Centaurus]

when it does start to move in the wrong direction we instinctively hit the brakes, making matters worse.

Which is why pilots are wise to heed the recommendations in the B737 FCTM that if landing with a crosswind on a slippery runway, a directional control problem can occur. As the aircraft starts to weather vane into wind, the reverse thrust side force component adds to the crosswind component and drifts the aircraft to the downwind side of the runway. Also, high braking forces reduce the capability of the tyres to corner.

To correct back to the centreline, release the brakes and reduce reverse thrust to reverse idle. Releasing the brakes increases the tyre-cornering capability and contributes to the maintaining or regaining directional control. Setting reverse idle reduces the reverse thrust side force component without the requirement to go through a full reverser actual cycle.

Use rudder pedal steering and differential braking as required, to prevent over correcting past the runway centreline. When directional control is regained and the aircraft is correcting towards the runway centreline, apply maximum braking and symmetrical reverse thrust to stop the aircraft. Note that use of this technique increases the landing distance.

[PEI_3721]

Centaurus, A timely reminder.
The recovery procedure highlights further safety issues when landing on contaminated runways, in that credit for reverse thrust may be allowed in landing distance calculations, thus any reduction in retarding effort to regain control erodes distance margins. Also max braking is often recommended, thus there is no additional retardation is available when reapplying the brakes. Added to which, the time (thought) to disengage autobrake, that the margins in published data for contaminated landing might be less than those for normal conditions, and the inherent ambiguities in reporting contaminated runway conditions.
Thus any problems with crosswind control compound the landing task - regain directional control and maintain retardation.
Know before you go, good planning, and respect crosswinds in contaminated conditions.

[Centaurus]

To correct back to the centreline, release the brakes and reduce reverse thrust to reverse idle.

Adding to my own previous post. You have to plan which method of releasing autobrakes is applicable. Using extra brake pedal pressure to release them actually applies the brakes (however momentary that is) and may exacerbate the problem. Switching the autobrake off by its actuating switch may be better. That requires good crew cooperation and prior briefing. Also, reducing to reverse idle is not as simple as it sounds. Some aircraft (and their simulators) have a recognizable reverse detent, while others have hard to locate detents.

Obviously if the aircraft is broadsiding sideways in the crosswind, the action to obtain reverse idle must be swift and sure. Too far down towards reverse idle and before you know it you have missed the detent and gone to forward thrust either on both engines (if a twin) or asymmetric reverse thrust which makes matters worse.

With the time it takes for the N1 to reduce from full reverse to idle reverse taking several seconds, missing the reverse detent and into forward thrust could leave you with significant undesirable forward thrust just when you don't want it.

This is where practicing the manoeuvre in the simulator is invaluable because it takes several attempts to get the procedure right. It depends on the fidelity of the simulator of course and that means experimenting to obtain the required crosswind component and slippery surface conditions that start to get the aircraft (simulator) sliding sideways.

[flyboyike]

We were in DTW on Christmas morning, landed on 22R. Taxied North on Alpha, then Victor to hold short of 22L, then joined Kilo Northbound toward our gates. The runway was beautiful, but the taxiways were pretty treacherous. I had to keep at a crawl the whole time with while riding the brakes, especially due to higher idle with engine A/I being on and the airplane being VERY light. I was not happy. Wayne County usually does a better job than that!

[Phantom Driver]

Anchorage could be fun, at times. Snow clearing resources quite rightly targeted the runways , and so taxiways often suffered , especially on the cargo (R ) bays.

One night, the whole area was covered in snow , no centreline ( or other ) markings visible in the murk. It was deemed wise to shut down and get towed in.